/*
 * Copyright (C) 2012 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package interactivespaces.util.concurrency;

import interactivespaces.InteractiveSpacesException;

/**
 * A loop which controls a {@link Updateable}.
 *
 * @author Keith M. Hughes
 */
public class UpdateableLoop extends CancellableLoop {
	/**
	 * The object being updated.
	 */
	private Updateable updateable;
	
	/**
	 * Time in milliseconds to delay per loop.
	 */
	private long delayTime;

	public UpdateableLoop(Updateable updateable) {
		this.updateable = updateable;
	}

	@Override
	protected void loop() throws InterruptedException {
		updateable.update();
		
		Thread.sleep(delayTime);
	}

	/**
	 * Set a delay used between iterations.
	 * 
	 * <p>
	 * Will only be used if the delay is positive.
	 * 
	 * 
	 * @param delayTime
	 *            Number of milliseconds for the delay.
	 * 
	 * @throws InteractiveSpacesException
	 *             If loop is running.
	 */
	public void setDelayTime(long delayTime) {
		if (!isRunning()) {
			this.delayTime = delayTime;
		} else {
			throw new InteractiveSpacesException(
					"Can't change the delay time on a running loop");
		}
	}

	/**
	 * Set the delay time using frames per second.
	 * 
	 * @param fps
	 *            The loop rate in frames per second.
	 */
	public void setFrameRate(double fps) {
		setDelayTime((long) (1000.0 / fps));
	}
}
